1. Field of the Invention
The present invention relates to switch apparatuses primarily for use in the operation of an air conditioner, audio equipment and the like installed in automobiles.
2. Background Art
In recent years, a switch apparatus in which buttons are arranged is generally installed on the front panel of a cabin for control of various electronic equipment such as air conditioner and audio equipment. A description of such conventional switch apparatus is given referring to FIG. 5 to FIG. 7.
FIG. 5 is a sectional view of a conventional switch apparatus. FIG. 6 is an exploded perspective view of the conventional switch apparatus. Supporting sections 1A that are hollow and cylindrical and project upwardly are provided on case 1 made of an insulating resin and claw-like catch sections 1B are provided on the four exterior sides of supporting sections 1A. Engaging hole 2A is provided on each of the four sides of button 2 made of an insulating resin. Catch section 1B is inserted into engaging hole 2A and button 2 is mounted in a manner vertically movable relative to supporting section 1A.
Conductive patterns (not drawn) are formed on the top and bottom surfaces of wiring board 3, and push switches 4 are mounted on the top surface, thereby switch contacts are configured. Depressing section 2B that projects downward is provided on the bottom of button 2 and the bottom end thereof comes into contact with push switch 4. A switch apparatus is configured by covering push switch 4 and the top surface of wiring board 3 with cover 1.
In the above configuration, when button 2 on the right, for example, is depressed as shown in FIG. 7, button 2 moves downward and depressing section 2B depresses push switch 4 on the right. With this, electrical on-off action is performed inside switch 4. When the depressing force on button 2 is released, button 2 returns to the state as shown in FIG. 5 by the returning force of push switch 4.
In a switch apparatus as configured in this way, claw-like catch sections 1B are provided on the exterior surfaces of support section 1A in order to mount button 2 on case 1 and prevent it from falling. When forming such a partially projecting catch section 1B using an upper and a lower dies, a pin (not drawn) that extends down to the bottom end of catch section 1B along the exterior surface of support section 1A is required. Accordingly, when forming case 1 with dies, opening 1C having approximately the same width as that of catch section 1B is formed near the foot of support section 1A on the top surface of case 1 through which the pin pierced.
Alternatively, catch section 1B may also be formed by providing a slide pin on a die that can move in all directions relative to the four exterior sides of support section 1A when forming case 1. In this case, the die structure is complicated and fabrication is difficult when support sections 1A project upward of case 1 as described above and their spacing is small.
Such a switch apparatus is disclosed in Japanese Patent Application Unexamined Publication No. 2001-28367, for example.
In the conventional switch apparatus as described above, opening 1C is formed on the foot of support section 1A on the top surface of case 1. Accordingly, when installing it in a cabin of an automobile for operating an air conditioner and audio equipment, water and dust tend to enter into the switch apparatus through opening 1C and may cause trouble in switching operation.